A single speck of residue from the gun used to kill Jill Dando was found in the pocket of the coat worn by Barry George.

The particle was a perfect match with others found in the TV presenter's hair. It was, said the Crown, "compelling evidence" of his guilt.

At the scene of the crime, forensic scientists also found a single strand of fibre that matched George's trousers.

And eye witnesses saw George close to the presenter's home in Fulham in the hours before she was killed.

Inexplicable

Taken together, the jury was told, these strands of evidence showed that Barry George must have been the killer.

Police found this magazine and others at George's home

But why this disturbed man, with a history of psychological problems, decided to kill Jill Dando is still unclear. Two years on, the crime still seems inexplicable.

It is one of a very few crimes that can truly be said to have stunned the country. The jury was told: "She had a place in everyone's heart."

The Queen joined in the expressions of sympathy, and rewards totalling £250,000 were offered for the capture of the killer.

Jill Dando won fame presenting news programmes, and went on to become one of the nation's most popular broadcasters in series like Crimewatch and the Holiday programme.

No enemies

She was a young woman with a zest for life, and seemingly without an enemy in the world.

The theories

A Serbian hitman, seeking revenge for NATO's bombing of TV station

An underworld contract killing, to silence the voice of Crimewatch

An obsessive fan who wanted to be close to her

Yet on the doorstep of her home in Fulham, in broad daylight, Barry George placed his gun to her head and killed her with a single shot.

But it was more than a year before he was arrested and charged.

Because of the cold-blooded nature of the crime, it was initially thought the TV presenter could have been the target of a hitman.

It was suggested her death was a reprisal for the NATO attack on a TV station in Belgrade. She had recently fronted an appeal for Kosovan refugees.

But according to another theory, the killer was hired by someone in the underworld, upset over Jill's work with the Crimewatch programme.

Few leads

Both ideas seemed incredible. But despite all the publicity surrounding the case, detectives had little to go on.

A sweating man was seen getting onto a number 74 bus, but was never traced.

The fatal shot: clues from the cartridge case

A Range Rover was spotted near Jill Dando's home, but the vehicle could not be traced.

A gun was later found on the banks of the Thames, but turned out not to be the murder weapon.

But one clue that the police did have was the ammunition used by the killer. There were unusual crimping marks on the cartridge case, and the pistol used had a smooth bore, rare for a handgun.

Clairvoyants

In any murder investigation, the police look first at those close to the victim. But in the case of Jill Dando, the possibility that it could have been a crime of passion was quickly ruled out.

There was never any doubt about the public's desire to help catch the killer. Criminals contacted detectives to say they were sure the killing was not the work of a hit man.

Clothes found at flat matched description of killer

Clairvoyants and psychics offered advice to Scotland Yard. But one year after Jill's death, the police appeared no closer to catching her killer.

Detectives focused on the possibility that the murder was the work of an obsessive fan who had been stalking her. They identified people who had an "unhealthy interest" in the television presenter.

A psychologist helped to draw up a profile of the likely killer. As the police narrowed down the list of suspects, they became increasingly interested in Barry George, who lived just half a mile from Jill Dando's home.

Obsessions

When they searched his flat, they found it strewn with papers and magazines that showed him to have a fascination with guns, celebrities, and the BBC.

Detectives found copies of the BBC's in-house newspaper, published after Jill's murder, and featuring her picture on the front page.

Key evidence against Barry George

His interest in celebrities and the BBC

Fascination with guns

Trace of gunfire residue on his coat

A fibre from his trousers at crime scene

Seen near Jill Dando's home before shooting

He had learned about weapons after enlisting in the Territorial Army, and had also spent time at a local pistol club.

After nearly four days of questioning, he was charged with the murder of Jill Dando. According to the prosecution, he told "a pack of lies" in his efforts to establish an alibi.

In court, George's lawyers tried to discredit the scientific evidence, and said the Crown had failed to establish a motive for the crime.

They pointed to a police intelligence report that suggested that the killing could have been the work of a Serbian hitman.

But counsel for the Crown, Orlando Pownall, told the jury there was no evidence to support this "headline grabbing" claim.

Mr Pownall asked the jury: "Why would such a person want to kill her?"

Legacy

The conviction of Barry George brings an end to a perplexing case.

Her legacy: the fight against crime

The public's desire for the killer to be brought to justice had placed enormous pressure on the police.

There will be satisfaction at Scotland Yard that a difficult two-year investigation has finally been brought to a close.

Given the importance of scientific evidence in bringing her killer to justice, is it perhaps fitting that this year has seen the opening in London of the Jill Dando Institute for Crime Science.

The search for new ways to detect and prevent crimes will be her lasting memorial.